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    <meta charset="UTF-8">
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    <title>Document</title>
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<script>
    let arr=["one","two","therr"]
    let arr1=[...arr]
    arr1[1]="love"
    console.log(arr1)


    const err={
        a:undefined,
        
    }

    let e={a:1,b:2,b:3}
    let f={a:3,b:2,c:2}
    let c=[...e,...f]
    console.log(c)
</script>
</html>